feat(signal_v2): stock_client + 6 integration tests

httpx async client with custom retry loop (max 3, exponential 1s/2s/4s),
memory dict cache (portfolio 60s / news-sentiment 300s / screener 60s),
X-WebAI-Key auth header injection. Stale fallback returns last
successful response with logger.warning on persistent failures.

6 integration tests pass with respx httpx mock.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

signal_v2/tests/conftest.py

@@ -0,0 +1,18 @@
+"""Pytest fixtures for signal_v2 tests."""
+from pathlib import Path
+
+import pytest
+import respx
+
+
+@pytest.fixture
+def tmp_dedup_db(tmp_path) -> Path:
+    """SQLite 단위 테스트용 임시 DB path."""
+    return tmp_path / "test_signal_v2.db"
+
+
+@pytest.fixture
+def mock_stock_api():
+    """respx 로 stock API mock. base_url 은 테스트마다 임의."""
+    with respx.mock(base_url="https://test.stock.local", assert_all_called=False) as mock:
+        yield mock

signal_v2/tests/test_stock_client.py

@@ -0,0 +1,168 @@
+"""Tests for stock_client.StockClient."""
+import asyncio
+import logging
+import pytest
+import httpx
+
+from signal_v2.stock_client import StockClient
+
+
+BASE_URL = "https://test.stock.local"
+API_KEY = "test-secret"
+
+
+async def test_get_portfolio_normal_returns_dict_with_pnl_pct(mock_stock_api):
+    """정상 200 응답 + cache 저장."""
+    mock_stock_api.get("/api/webai/portfolio").mock(
+        return_value=httpx.Response(
+            200,
+            json={
+                "holdings": [{"ticker": "005930", "pnl_pct": 0.047}],
+                "cash": [],
+                "summary": {},
+            },
+        )
+    )
+    client = StockClient(BASE_URL, API_KEY)
+    try:
+        result = await client.get_portfolio()
+        assert result["holdings"][0]["pnl_pct"] == 0.047
+        # Cache populated
+        assert len(client._cache) >= 1
+    finally:
+        await client.close()
+
+
+async def test_get_portfolio_uses_cache_within_ttl(mock_stock_api):
+    """60s TTL 내 두번째 호출 = mock 콜 1회."""
+    route = mock_stock_api.get("/api/webai/portfolio").mock(
+        return_value=httpx.Response(
+            200, json={"holdings": [], "cash": [], "summary": {}}
+        )
+    )
+    client = StockClient(BASE_URL, API_KEY)
+    try:
+        await client.get_portfolio()
+        await client.get_portfolio()  # second call within TTL
+        assert route.call_count == 1
+    finally:
+        await client.close()
+
+
+async def test_get_portfolio_refetches_after_ttl_expiry(mock_stock_api, monkeypatch):
+    """TTL 만료 후 재호출 = mock 콜 2회. time.monotonic 모킹."""
+    route = mock_stock_api.get("/api/webai/portfolio").mock(
+        return_value=httpx.Response(
+            200, json={"holdings": [], "cash": [], "summary": {}}
+        )
+    )
+    # Fake clock: starts at 0, jumps to 61 between calls
+    fake_time = [0.0]
+    monkeypatch.setattr(
+        "signal_v2.stock_client.time.monotonic", lambda: fake_time[0]
+    )
+
+    client = StockClient(BASE_URL, API_KEY)
+    try:
+        await client.get_portfolio()
+        fake_time[0] = 61.0  # 60s TTL 만료
+        await client.get_portfolio()
+        assert route.call_count == 2
+    finally:
+        await client.close()
+
+
+async def test_get_portfolio_retries_3_times_on_timeout(mock_stock_api, monkeypatch):
+    """timeout 2번 + 200 1번 → 최종 성공. exponential sleep 호출 검증."""
+    sleep_calls = []
+
+    async def fake_sleep(s):
+        sleep_calls.append(s)
+
+    monkeypatch.setattr("asyncio.sleep", fake_sleep)
+
+    mock_stock_api.get("/api/webai/portfolio").mock(
+        side_effect=[
+            httpx.TimeoutException("timeout 1"),
+            httpx.TimeoutException("timeout 2"),
+            httpx.Response(
+                200, json={"holdings": [], "cash": [], "summary": {}}
+            ),
+        ]
+    )
+    client = StockClient(BASE_URL, API_KEY)
+    try:
+        result = await client.get_portfolio()
+        assert result["holdings"] == []
+        assert sleep_calls == [1, 2]  # exponential 1s, 2s
+    finally:
+        await client.close()
+
+
+async def test_get_portfolio_429_triggers_backoff(mock_stock_api, monkeypatch):
+    """429 → 1s backoff → 200."""
+    sleep_calls = []
+
+    async def fake_sleep(s):
+        sleep_calls.append(s)
+
+    monkeypatch.setattr("asyncio.sleep", fake_sleep)
+
+    mock_stock_api.get("/api/webai/portfolio").mock(
+        side_effect=[
+            httpx.Response(429, text="rate limit"),
+            httpx.Response(
+                200, json={"holdings": [], "cash": [], "summary": {}}
+            ),
+        ]
+    )
+    client = StockClient(BASE_URL, API_KEY)
+    try:
+        result = await client.get_portfolio()
+        assert result["holdings"] == []
+        assert sleep_calls == [1]
+    finally:
+        await client.close()
+
+
+async def test_get_portfolio_falls_back_to_stale_on_all_failures(
+    mock_stock_api, monkeypatch, caplog
+):
+    """cache 에 이전 성공 응답 + 모든 retry 5xx → stale 반환 + logger.warning."""
+    # No-op sleep for fast test
+    async def fake_sleep(s):
+        return None
+    monkeypatch.setattr("asyncio.sleep", fake_sleep)
+
+    # Patch time.monotonic BEFORE first call so cached timestamp uses fake clock
+    fake_time = [0.0]
+    monkeypatch.setattr(
+        "signal_v2.stock_client.time.monotonic", lambda: fake_time[0]
+    )
+
+    # First call succeeds
+    route1 = mock_stock_api.get("/api/webai/portfolio").mock(
+        return_value=httpx.Response(
+            200,
+            json={"holdings": [{"ticker": "005930"}], "cash": [], "summary": {}},
+        )
+    )
+    client = StockClient(BASE_URL, API_KEY)
+    try:
+        first = await client.get_portfolio()
+        assert first["holdings"][0]["ticker"] == "005930"
+
+        # Advance fake clock past TTL (60s) so cache is stale
+        fake_time[0] = 61.0
+
+        # Now mock to return 500s persistently
+        route1.mock(return_value=httpx.Response(500, text="server error"))
+
+        with caplog.at_level(logging.WARNING, logger="signal_v2.stock_client"):
+            result = await client.get_portfolio()
+            assert result["holdings"][0]["ticker"] == "005930"  # stale data returned
+            assert any(
+                "stale" in rec.message.lower() for rec in caplog.records
+            )
+    finally:
+        await client.close()